The Voyager spacecraft will be the third and fourth human artifacts to escape entirely from the solar system. Pioneers 10 and 11 ... both carried small metal plaques identifying their time and place of origin for the benefit of any other spacefarers that might find them in the distant future. ... NASA placed a more ambitious message aboard Voyager 1 and 2-a kind of time capsule, intended to communicate a story of our world to extraterrestrials.
http://vraptor.jpl.nasa.gov/voyager/record.html

But for an even more detailed record of the voyager message, see the official site,
http://voyager.jpl.nasa.gov/